scholarly journals ESTIMATES OF LONG WAVES IN THE WESER ESTUARY

1984 ◽  
Vol 1 (19) ◽  
pp. 53
Author(s):  
V. Barthel ◽  
E.R. Funke
Keyword(s):  
Wave Climate ◽  
Long Waves ◽  
Sea State ◽  
Floating Structures ◽  
Weser Estuary ◽  
Model Studies ◽  
The North ◽  
Frequency Components ◽  
The North Sea ◽  
Harbour Oscillations

Long waves of small amplitudes can excite harbour oscillations as well as the motion of floating structures or vessels. Field data from the Weser Estuary, German Bight of the North Sea were analysed with respect to waves with periods greater than 8 s. After preprocessing of the mostly noisy data records, special analysis incorporated the reconstruction of incorrectly recorded frequency components below .03 Hz and bivariate distributions of heights and periods. Results suggest that long wave activity increases towards the inner estuary. Grouping properties are dependent on wind direction and on directionality of the sea state. Further investigations and model studies for the response of travelling vessels to this wave climate are recommended.

scholarly journals Influence of Sea State on Sea Surface Height Oscillation from Doppler Altimeter Measurements in the North Sea

2018 ◽  
Vol 10 (7) ◽  
pp. 1100 ◽  
Author(s):  
Ferdinando Reale ◽  
Fabio Dentale ◽  
Eugenio Carratelli ◽  
Luciana Fenoglio-Marc
Keyword(s):  
North Sea ◽  
Sea Surface Height ◽  
Sea Surface ◽  
Sea State ◽  
The North ◽  
The North Sea

scholarly journals Wave current interaction: Effect on force prediction for fixed offshore structures

2018 ◽  
Vol 203 ◽  
pp. 01011
Author(s):  
Mohamed Latheef ◽  
Nasir Abdulla ◽  
Mohd Faieez Mohd Jupri
Keyword(s):  
Vertical Structure ◽  
Offshore Structures ◽  
Base Shear ◽  
Sea State ◽  
Clear Trend ◽  
The North ◽  
Relative Water ◽  
The North Sea ◽  
Current Interaction ◽  
Typical Design

MetOcean conditions in the South China Sea (SCS) indicates that unlike other locations such as the North Sea, the magnitude of the currents can be relatively large. In addition, these currents are strongly sheared. The present study focused on the typical design problem of calculating the ultimate base shear and overturning moments for slender fixed structureswiththe inclusion of the interaction between the currents and the wave field. It has been found that the loads on average can be around 15% larger when this interaction is accounted for in the calculation of the loads, highlighting the importance. In addition, the level of these amplifications were found to be dependent on the sea state steepness and the relative water depth. While no clear trend was found (changed case by case) in the present work, incorporating the vertical structure of the current was found to change the pattern of the amplification of the loads.

Spectral wave climate of the North Sea

2007 ◽  
Vol 29 (3) ◽  
pp. 146-154 ◽  
Author(s):  
Alexander V. Boukhanovsky ◽  
Leonid J. Lopatoukhin ◽  
C. Guedes Soares
Keyword(s):  
North Sea ◽  
Wave Climate ◽  
The North ◽  
The North Sea

Statistics of Greater Sea States

2011 ◽  
Author(s):  
Anne M. Fullerton ◽  
Thomas C. Fu
Keyword(s):  
Numerical Models ◽  
Ship Motions ◽  
Frequency Range ◽  
Sea State ◽  
The North ◽  
Spectral Models ◽  
Wave Heights ◽  
The North Sea ◽  
Computational Predictions ◽  
The Ideal

Accurate representations of seaway statistics are important for physical and computational predictions of ship motions. The spectra that are most typically used in these applications are the Pierson-Moskowitz or Bretschneider. While these spectra are useful for fully developed seas, the larger sea states (Sea State (SS) 7 and higher) are typically not fully developed. In these cases, other spectral models may be more appropriate. It is critical to ship motion prediction, for both physical and numerical models, to accurately capture the frequency range for the sea state of interest. Sea state statistics, including wave heights, periods, and spectral bandwidths from various buoys and a platform in the North Sea are collected and compared with statistics from lower sea states. The spectral data are then averaged to generate a typical spectrum under the measured conditions. These developed spectra are compared with the ideal spectra mentioned previously.

Impact of Climate Change on the North Sea Offshore Energy Sector

2018 ◽  
Author(s):  
Nicolas Fournier ◽  
Galina Guentchev ◽  
Justin Krijnen ◽  
Andy Saulter ◽  
Caroline Acton ◽  
...  
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
North Sea ◽  
Wave Climate ◽  
Energy Industry ◽  
Strong Impact ◽  
Impact Of Climate Change ◽  
The North ◽  
Climate Indicators ◽  
The North Sea

The complex nature of the energy industry across extraction, transportation, processing, delivery and decommissioning creates significant challenges to how the sector responds, adapts and mitigates against risks posed by the changing future climate. Any disruption in this interconnected system will affect both industry and society. For example, in the summer of 2005 Hurricane Katrina and a month later Hurricane Rita had wide reaching impacts on the US offshore Oil and Gas industry which resulted in an increase in global oil prices due to loss of production and refinery shutdowns in the Gulf of Mexico. Preparing, mitigating and adapting to these climate changes is dependent upon identifying appropriate climate indicators as well as the associated critical operational thresholds and design criteria of the identified vulnerable assets. The characterization and understanding of the likely changes in these climate indicators will form the basis for adaptation plans and mitigating actions. The Met Office in collaboration with energy industry partners, under the Copernicus Clim4energy European project, has developed a Climate Change Risk Assessment tool, which allows the visualization and extraction of the most recent sea level and wave climate information to evaluate their future changes. This study illustrates the application of this tool for evaluation of the potential vulnerability of an offshore infrastructure in the North Sea. The analysis shows that for this asset there is a small increase in sea level of 0.20–0.30 m at the location of interest by 2050. However, there is a small decrease or no consistent changes projected in the future wave climate. This wave signal is small compared to the uncertainty of the wave projections and the associated inter-annual variability. Therefore, for the 2050s time horizon, at the location of interest, there is no strong impact of climate change at the annual scale on the significant wave height, the sea level and thus the associated climate change driven extreme water level. However, further analysis are required at the seasonal and monthly scales.

scholarly journals WAVE CLIMATE ANALYSIS FOR ENGINEERING PURPOSE

1976 ◽  
Vol 1 (15) ◽  
pp. 2 ◽  
Author(s):  
Hans H. Dette ◽  
Alfred Fuhrboter
Keyword(s):  
Wave Climate ◽  
Incoming Wave ◽  
Offshore Area ◽  
The North ◽  
Wave Measurements ◽  
Wind Velocities ◽  
Wave Heights ◽  
The North Sea ◽  
One Year ◽  
Climate Analysis

The North Sea (Fig. 1) is known as a random sea with depths in the southern part between 40 m and 100 m so that in contrary to the Atlantic and Pacific coastlines deep sea wave conditions do not exist. After four years of comprehensive wave measurements in the offshore area of the Island of Sylt near the Danish border a general analysis of the wave climate in that region was possible. In this paper results and suggestions will be presented under the aspect of replacing qualitative judgements by quantitative statements which are derived from the knowledge of the adjacent wave climate. Because the wave action varies from year to year a general time unit is not advisable for the evaluation of shore processes; therefore the time scale should be substituted by the integral of incoming wave energy occurring after a certain time. The investigated method of expressing the total energy of one season or one year in the electrical unit Kilowatthour (kWh) per meter (m) width of shoreline could prove in future as a feasible way of classifying the irregular seasonal and yearly wave intensities. It is further shown that wave measurements over a period of several years can be sufficient for the investigation of correlations between the wind velocities occurring from all directions and the resulting wave heights. In case of satisfying correlation factors it will then be possible to carry out feedback operations for periods from which only records of wind velocities and directions are available and even to hindcast the wave heights for certain not yet measured wind velocities.

Airborne GNSS reflectometry for coastal monitoring of sea state

2020 ◽  
Author(s):  
Mario Moreno ◽  
Maximilian Semmling ◽  
Georges Stienne ◽  
Serge Reboul ◽  
Jens Wickert
Keyword(s):  
Carrier Phase ◽  
Signal Amplitude ◽  
Navigation Systems ◽  
Sea State ◽  
Wind Retrieval ◽  
The North ◽  
Front End ◽  
The North Sea ◽  
Gnss Reflectometry ◽  
Satellite Navigation Systems

<p>Global Satellite Navigation Systems (GNSS) applications like navigation and positioning generally focus on the use of the direct radio signal broadcasted by the navigation satellites. From these signals, very highly precise coordinates can be obtained. However, there is a proportion of signals, that do not reach the receivers directly, that is, the signals that are reflected off Earth’s surface before reaching the receivers. That phenomenon gave way to one of the techniques that is taking an important role in the scope of GNSS remote sensing called GNSS-Reflectometry (GNSS-R). Due to the high reflection coefficient of the water and its importance within the climate system, the ocean is one of the surfaces with greatest interest in GNSS-R research projects. The objective of this study is to retrieve information about ocean height measured through the delay of the signal, and sea state and wind retrieval (ocean surface roughness) from the analysis of the signal amplitude.</p><p>During this study, GNSS-R measurements were executed along the North Sea coast between the cities of Calais and Boulogne, France, onboard of a gyrocopter. The setup consisted of a front-end data recorder with a right-handed circular polarization (RHCP) antenna. The campaign was conducted in July 2019 within a total of 9h 40m flight time. Each flight was performed at an altitude of about 800 m above sea level going on two legs forth and back along the coast. The legs differed in the distance from the coastline, of 700 m and 2 km, respectively.</p><p>Reflectometry signal processing involves three data levels. Level (0): The raw data samples of Syntony front-end receiver. Level (1): The Delay-Doppler Map (DDM) of the correlated reflected signal and the carrier phase, from which geophysical information can be derived. And Level (2): height estimation (from signal correlation in delay and frequency domain) and roughness estimation (from signal amplitude).</p><p>By using the DDM and the carrier phase delay the sea state shall be assessed including the achievable precision and reliability of estimates. An additional aim is also to validate the configuration in terms of the used platform, antenna setup, and flight design.</p>

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